Invasive or Non invasive paternity testing while pregnant

There are many reasons why you would want to have paternity testing when pregnant rather than waiting till after the birth of the baby. There are three options available that depends on the trimester the mother is in and also whether you opt for an invasive or a non-invasive procedure for the prenatal testing. A DNA paternity test can be accurately performed before the birth of the baby but costs anything between $1000-$2000. When opting for a paternity test, make sure that the laboratory carrying out the analysis has been accredited by the AABB and ISO 17025.

The results of the DNA test are usually made available within a time frame of a few business days. If the costs and risks feel too high, you might want to wait till the birth of the child and carry out a home paternity test. This is far cheaper and quicker. In terms of prenatal testing for paternity, you need to decide whether you want to opt for a risk free and non invasive test or a risky fetal sampling method such as amniocentesis and CVS (discussed below).

Why analyse fetal DNA?

Analysing your baby’s DNA ensure that your baby is developing healthily and that your pregnancy progresses without any complications. You will not need to undergo fetal sampling methods such as amniocentesis and CVs (discussed hereunder) unless the OBGYN suspects there might be a chance of your baby having an autoimmune disease such as sickle cell or Down’s syndrome. Usually, ultrasounds may suggest the baby might be suffering from an autoimmune diseases but doctors cannot confirm this accurately with just ultrasound results. They would in such cases, suggest analysis of fetal DNA samples extracted from within the womb.

1. Chorionic Villus Sampling (CVS):

Chorionic Villus Sampling is an invasive type of sampling – a biopsy of chorionic villi. The test is generally performed during the first trimester of pregnancy i.e. around 8-13 weeks of pregnancy. CVS is performed by inserting a catheter through the cervix and taking a sample from outside the gestational sac. During this procedure, the obstetrician obtains a small amount of fetal chorionic villi which is used in the paternity test. This test is extremely accurate. However, it is mandatory to seek doctor’s advice before going in for this procedure.

2. Amniocentesis:

Amniocentesis is a pre natal paternity test that is usually performed during the later stages of pregnancy. During this procedure, around 10 ml of amniotic fluid is taken out transabdonimally by the obstetrician. Amniotic fluid is the best sample for paternity testing and is extremely accurate. This test can be performed in the second trimester of pregnancy between 14-20 weeks. The obstetrician, during this procedure, is guided by ultrasound to guide a thin needle inside the uterus and through the abdomen. The needle, with light suction, draws out a small quantity of amniotic fluid which is used for DNA analysis. The dilemma many face is that in amniocentesis, there is a small risk of miscarriage or harm to the baby. This procedure has other side effects such as vaginal bleeding, leaking of amniotic fluid and cramping. Once samples are collected they must be available at the laboratory within the shortest time frame possible. Scientists then use a DNA analysis and mass replication technique known as Polymerase chain reaction to analyse samples.

3. SNP microarray procedure:

There is another alternative to the invasive procedures and that is the SNP microarray procedure which makes it possible to carry out non invasive paternity testing in pregnancy. This method is risk free and there will be no remote chances of harming the fetus or the mother. The mother’s blood contains fetal DNA of the baby that she is carrying as it flows inside the maternal blood stream via the placenta. Earlier, scientists did not know how to isolate the DNA from maternal blood, however, the latest SNP microarray has made that possible. This non invasive paternity test does not require the insertion of a needle inside the mother’s womb for sample, rather it makes use of the latest technology that analyzes the baby’s DNA that is present in the mother’s bloodstream. This test has a high rate of accuracy, 99.9% and is a much safer option that will not harm the baby in any way.

There are times when it becomes pertinent to know the paternity of an unborn child for various reasons. However, it is important to decide the procedure that would solve the purpose and would not harm the baby or the mother in any way. It is important to take the advise of an obstetrician before finalizing the procedure to make sure that no accidents happen while conducting the procedure.